PVC and Polymer Distribution

CJP Sales Ltd

Injection Moulded and Extruded UPVC

Components

Weathering and Warranties

October 2012

CJP Sales Ltd

PVC and Polymer Distribution

Weathering and Warranties

CJP Sales Technical Bulletin

High impact weathering

This bulletin is designed to

help understand how UPVC

Mouldings and Extrusions

perform in service and to

explain how UPVC grades are

selected and how they are

formulated.

UPVC offers very good

resistance to weathering has

very good light fastness for

outdoor applications and

provides good colour reten-

tion when subject to UV light.

In order to make this possible

the UPVC formulation must

contain a good quality stabi-

liser package and a high level

of good quality pigment. This

also needs to be balanced with

process aid and lubrication to

allow it to be processed

through an injection moulding

machine and a complex mould

tool.

In order to achieve good col-

our retention a number of fac-

tors need to be taken in to

consideration.

* The location of the finished

component and the time it is

in direct sun light.

* What level of colour fade is

acceptable and over what

period? Everything fades in

the sun, but to what level over

what period of time?

* Processing the moulded

products is a factor. Each

grade contains stabiliser which

absorbs energy, such as Heat,

Radiation and UV Radiation.

All of these factors affect the

stability of the PVC. The

stabiliser package within the

grade allows it to be

compounded, moulded and

provides the long term stabil-

ity for colour fastness. If the

moulding process uses too

much stabiliser there may not

be enough left for long term

environmental stability. (See

Processing Guide)

Page 1

Vicat Softening Point

The vicat softening point is the temperature at which the material actively starts to soften. At this point, the

mechanical properties start reducing and components can deform under pressure. It is not ideal to use UPVC

where a maximum service temperature of 55c is required. The main area for concern is handling and packaging

of components as they can become deformed if left in a vehicle or steel container during periods of hot

weather.

The mouldings on the left have a vicat of 65c on the right

both were heated to 45c and put under pressure.

CJP Sales Ltd

PVC and Polymer Distribution

CJP Sales Technical Bulletin

Standard UPVC Moulding grades

DVJ 503/210—Window accessory

grade.

RM734—Window parts and pipe

fittings grade.

PVC grades offered for outdoor use

are engineered with high quality

Calcium Zinc Stabilisers and very

good lubrication packages, which

help the moulding process and re-

duce the stabiliser used. They offer

a high quality medium impact and a

good high gloss surface finish with a

vicat softening point between 65c

and 78c.

Page 2

CJP Sales Ltd

PVC and Polymer Distribution

CJP Sales Technical Bulletin

www.cjpsales.co.uk

Moulding Grades and

Extrusion Grades

There is a mis -conception

that Moulding and extrusion

grades are the same. Unfor-

tunately this is not the case,

the basic raw materials are

the same, however, they are

engineered to process in

different ways. Injection

moulding grades need a very

high pressure to break down

the compound to enable it to

fill the tool; this increases the

use of stabiliser and reduces

the mechanical properties

(strength). Extrusion grades

are designed to process with

lower pressure and don’t re-

quire such a high flow, which

uses fewer stabilisers, and

maintains the mechanical

properties.

High Impact grades

DVX5125/206— Pipe fittings

hollow tubes and fittings.

These use the same high

quality Calcium Zinc Stabiliser

package and are also easy to

process grades. They have

been impact modified and

have additional process aids

which improve the impact,

without reducing the weath-

ering properties, and have a

vicat of 76c.

These grades are formulated

to process on a wide range of

injection moulding machines

and mould tools and when

processed with care, perform

without signs of degradation.

Extrusion Moulding

Page 3

Weathering Properties

For white applications, the in-

dustry standard BS7413, states

a Delta E of 5 when exposed to

a Northern European Climate

for 10 years. In most cases, this

is achievable, as the mouldings

weather in line with the extru-

sions and it is very rare for

mouldings to fail. In order to

uphold this, the mouldings

would have to be measured

prior to sale and then again if a

failure occurs. At this point, all

other processing factors need

to be considered. It is possible

to degrade the material when

injection moulded , if the cor-

rect processing conditions are

not used. Obviously, this can

result in reduced performance.

DVJ 503/209 has provided a

Delta E reading of 1.5 after 15

years.

For colours it is more difficult

to predict the colour change,

as colour pigment light fast-

ness is visible. The picture to

the right shows DVJ503/210

natural with added Vynacol

Masterbatch in brown and

dark green. The weathering

and colour retention is good

but does not compare to simi-

lar weathering conditions with

white components.

Tropical Grades

Grades that are specifically designed

for tropical climates contain a high

level of Titanium Dioxide white pig-

ments, typically up to 7- 8 parts. This

is workable in an extrusion grade but

can actually reduce the long term

colour stability in a moulding grade.

This is due to the level of pigments

affecting the moulding ability of the

grade and using up the stabilisers. In

weathering tests DVJ 503/210 has

performed better for light fastness

because of its ease of processing,

resulting in less stabiliser being used.

The stabilisers in a formulation

are designed to stabilise through

the compounding process and

through the injection moulding

or extrusion process. It is very

important to ensure that the

processing conditions are set

correctly and the compound is

not over heated, in order to

retain stabiliser for the long

term weathering protection. It

is unusual to receive complaints

regarding the colour fading of

white moulded products, even

when used in tropical climates.

Unfortunately there are no hard

and fast guarantees available,

we can assure you that our

grades are formulated with the

highest level of stabiliser and

quality pigments available.

When tested in the laboratory,

under accelerated weathering

conditions, and over a 3 month

period, grades pass the Delta E

test. However how they perform

after moulding, and in which

environment they are subjected

to, is out of our control. “

CJP Sales Technical Bulletin

Conclusion

Many concerns come about because

customers want guarantees relating

to weathering performance. It is

important to realise that the grades

formulated contain the stabilisers

that will provide long term weather-

ing and light fastness properties.

For further information please contact: CJP Sales Ltd: 01656 644907

www.cjpsales.co.uk sales@cjpsales.co.uk

Page 4

Vynacol Masterbatch and Natural UPVC